Fig. 19. The nucleus (N) of the anterior pigment epithelium of the iris is situated between the posterior pigment epithelium (P) and iris stroma (S). Pigment granules (pg) are present in the apical portion of the anterior pigment epithelium and bundles of myofilaments (between arrowheads) representing the iris sphincter muscle are present in the basal portion of the cell (×7250).